Hi Clark,
Does the new temperature object remain in the field of view of the TMP006 for the entire duration of this test? Or is the object placed in the field of view and then removed? The TMP006 is essentially integrating all of the infrared energy within its field of view, although there is a weighting factor depending on where the object falls within the field of view:
Therefore, any object radiating infrared energy within the field of view will affect the measured temperature, even if it is not the object the part is directly pointed at.